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Derivatives, Hedging Programs and Other Financial Instruments, Narrative (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Collateral posted for net derivatives	$ 0					$ 0
Customer collateral deposits	$ 0					0
Maturity period of short-term investments	12 months
Designated as Hedging Instrument \| Purchase
Derivative [Line Items]
Derivative net liability	$ 3,100,000					$ 100,000
Scenario, Forecast \| Natural Gas
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage		63.00%	67.00%	68.00%	70.00%
Scenario, Forecast \| Electricity
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage		9.00%	54.00%	54.00%	53.00%